Microprocessor vendors typically develop a family of processors designed around a given processor architecture and then continuously evolve the architecture. For example, Intel Corporation has developed several generations of processors around its x86 architecture, the most recent being the PENTIUM® family of microprocessors. Similarly, Advanced Micro Devices, Inc. has developed families of processors designed around its x64 architecture. Often a processor vendor will add a feature to an existing model or family of processors. Examples of new features that have been added to a processor family include the Physical Address Extension (PAE), MMX instructions, and streaming SIMD extensions (SSE) features added to the PENTIUM® family of processors.
Features that add additional bits to existing registers within a processor, that add new registers to the processor, or that require additional processor state to be saved and restored across processor context switches can be problematic for both processor vendors and developers of operating systems designed to execute on such a processor. In particular, in order for an operating system to use such a feature or to make such a feature available to application programs, the kernel of the operating system must be modified to support the new feature. This is true of both traditional operating system kernels, such as the kernel of the WINDOWS® operating system available from Microsoft Corporation, and so-called partitioning kernels that provide partitioned execution environments for multiple “guest” operating systems. Because these kinds of new features require support in the kernel, the introduction of such a feature by a processor vendor is effectively gated on the release of an updated version of the kernel.
The existence of new features in a processor presents additional problems for partitioning kernels. A partitioning kernel provides a separate, partitioned execution environment for each of multiple “guest” operating systems running on a single computing system. While each operating system runs in a separate partition, it appears to each operating system that it has full control of the underlying processor and other system components. In reality, the partitioning kernel presents one or more separate, virtualized processors to each operating system. It is important in such a system to prevent secrets from leaking between partitions and to prevent one partition from corrupting the state of another partition. However, if a new feature has been implemented in a processor on which the partitioning kernel is running and that feature adds new registers or additional bits to existing registers or adds to the processor state that must be saved during a context switch from one partition to another, the potential to leak secrets between partitions or for one partition to corrupt the state of another exists. Thus, it is particularly important for a partitioning kernel to be aware of any such new feature.
Thus, there is a need for a mechanism by which a processor vendor can make information concerning a new feature of a processor available to a computing system so that the system can detect, enable and manage operation of the new feature. The present invention satisfies this need.